The Billy Goat Trail is a 4.7-mile (7.6 km) hiking trail that follows a path between the C&O Canal and the Potomac River within the Chesapeake and Ohio Canal National Historical Park near Great Falls in Montgomery County, Maryland. Three trails traverse rough and rocky terrain at times, including a steep climb along a cliff face along the Potomac River's Mather Gorge. A flat and smooth tow path parallels along the C&O Canal.